Facsimile reception medium



Patented Apr. 27, 1943 FACSIMILE RECEPTION MEDIUM Robert H. Marriott,Brooklyn, N. Y., assignor to Finch Telecommunications, Inc., New York,N. Y., a corporation of Delaware No Drawing. Application February 9.1940, Serial No. 318,203

6 Claims.

My invention relates to a coating which may be converted by means ofheat so as to produce areas of different reflectivity, thus providingimages or characters on said coating. More particularly, my inventionrelates to a novel facsimile paper comprising a transparent coatingsuperimposed on to a conductive backing whereby upon electrical impulsesbeing transmitted from a stylus through the coating to a conductivebacking, the heat generated by the electrical impulse causes bubbleformation in the transparent coating with subsequent destruction of thebubble causing areas of refraction and reflectivity whose markedlychanged appearance from the remainder of the transparent coating may beemployed as print or pictures.

Although my invention is of general application, I am particularlyconcerned with the pro duction of a paper on which may be reproducedprint or pictures in accordance with impulses from a stylus movingacross said paper. For the general operation of facsimile devices fortransmission and reception of images, I refer to Finch Patents No.2,141,975 and No. Re. 19,575.

It has been difficult to provide a paper for receiving the images whichis both properly sensitive and of acceptable appearance at a reasonablecost.

I now provide a novel paper for the reception of facsimile images. Mypaper comprises an electro-conductive backing on which is coated atransparent layer of material which is adapted to be physically changedby the heat induced by an electric current which traverses the coating.The physical change which I refer to involves the formation of surfacesof different reflectivity or refraction than the remainder of thetransparent coating and these areas of different reflectivity andrefraction, therefore, may be employed to obtain images or print. As ananalogy these areas represent a cracked ice effect such as a skate mark,or an etched or ground glass effect, as against transparent ice or clearglass.

Specifically I employ as the conductive back ing for my compositefacsimile paper a paper impregnated with carbon. Such a carbonimpregnated paper is a good conductor. I then coat this carbon paper bybrushing, dipping, spraying or the like, with a layer of a watersolution of sodium silicate. I then dry this coating and the sodiumsilicate forms a clear glass like coating on the carbon impregnatedpaper.

The sodium silicate retains a certain amount of water. When this paperis used for facsimile reception a stylus as shown in Patent No. Re.

19,575 moves back and forth across the surface of the paper in slightpressure contact therewith and at particular points, in accordance withthe image being broadcast, electrical impulses at a voltage of up to 300volts are transmitted by the stylus through the coating to theconductive backing. However with my more sensitive paper, highervoltages and lower currents may be employed. These electrical impulsesgenerate heat in the particular areas which they contact and the heatcauses the water in the sodium silicate coating to expand to form watervapor and possible steam. This expansion causes the formation of bubblesand the bubbles customarily burst under this expanding force and thenfreeze in place as they are formed.

I wish to point out that the pressure action of the stylus in passingover these bubbles crushes them and tends to cause them to burst so thatthe areas of varied refraction and refiectivity similar to cracked iceare more readily formed.

Although it is possible to prevent the bubbles from bursting by the useof a lower temperature and by preventing a pressure contact of thestylus with the paper in which event irridescent bubbles are formed,which may for certain purposes be desired, I normally desire to formburst bubbles. the efl'ect of which produces an improved printappearance.

The sodium silicate is fire proof and does not support combustion.Therefore, the heat induced by electrical impulses does not burn thesodium silicate but simply physically changes it by the formation of thebubbles above referred to.

Since the paper backing which I normally employ as the base for myfacsimile paper is rather flexible, I prefer to add a small quantity ofglycerin or suitable plasticizing agent to the sodium silicate sincewithout the addition of this glycerin or its equivalent th sodiumsilicate has a tendency to make the paper still. and cause it to roll upor curl on contact with the moisture of the air. The glycerin furtheracts to hold the water in the silicate which is a hygroscopic agent initself. The glycerin, therefore, prevents the paper from curling and thesodium silicate from becoming stiff and, in addition, it retards theevaporation of the water therefrom.

The amount of glycerin is limited by the fact that an excess of glycerinacts to interfere with the proper passage of the current therethroughand hence reduces the amount of heat. Since it is necessary to developthe heat in the coating to vaporize the water and cause the formation ofbubbles to obtain the white cracked ice ap pearance, an excess ofglycerin is undesirable.

I have found that about a drop of glycerin to about 4 cc. of sodiumsilicate representing about to 1% of glycerin with respect to the sodiumsilicate is approximately the amount required.

I prefer to employ a thin coating of sodium silicate with or without theplasticizing agent on the carbon paper. Since the carbon paper is blackand the water bubbles, upon bursting, form a white cracked iceappearance, I obtain a white print on a black background which isaesthetically desirable in this art. I

Although I have described my paper as comprisingconductive backingcoated thereon with a substance adapted to bubble or crack under theinfluence of an electric current, the broader aspect of my inventioncovers the paper that would not necessarily have a conductive backing.In such event the break down of the coating could be effected by heatalone in the form of radiant heat focussed progressively on toparticular areas, the focussing efiecting a heating of the coating atthe particular points which would cause the bubbling or cracking effectfor the desired change in appearance of particular areas to form Wordsor pictures thereby.

In addition to using a focussed radiant heat, I may also employ a blastof hot air. Thus in this aspect of my invention, I may employ any basedesired together with a coating thereon, the coating being adapted to bephysically changed by heat produced, for example, by radiant heat orconducted heat to particular areas thereof to produce a physical changeand hence the changed appearance of relative areas to produce thedesired effect. The coatings in this case may be as described above, forexample, of sodium silicate or similar material, the appearance of whichmay be radically altered by heat.

As a means by which this could be carried out in a facsimile receivingapparatus I propose to use a strong radiant heat source which may befocussed on to a 'small area of the coating, thereby heating that areaand turning on and off or deflecting this heat effect in accordance withthe markings desired.

Similarly I could employ a stylus with a point which could be rapidlyheated while in contact with the coating to again produce the desiredphysical change in the coating by the heat effect.

The object of my invention is to provide a novel coating which may bephysically changed by heat in particular areas in order to reproducedesired images or characters.

It is another object of my invention to provide a novel transparentcoating, particular areas of which may be heated to cause the formationat those particular areas of bubbles or burst bubbles giving a crackedice appearance which is opaque.

It is a further object of my invention to provide a novel coating forfacsimile paper in which the characters are produced by causingformation oi burst bubbles or cracked ice appearance in particularareas.

It is a further object to provide a novel facsimile paper comprising aconductive backing, and a transparent coating.

It is a further object of my invention, therefore, to provide a coatingmaterial which may be so aiiected by heat applied to specific areasthereof so as to change the physical appearance of those specific areasfor the purpose .of reproducing images of printing or pictures, etc.,thereon.

It is a further object of my invention to provide a process forfacsimile reception in which I project radiant heat progressively on tospecific areas to change the physical appearance of these areas toproduce facsimile images.

Specifically my invention is directed to the provision of a paper whichcomprises a backing material, if such backing be necessary, andpositioned thereon a coating of a material such as sodium silicate whichis adapted to be acted upon by heat to produce areas of differentrefiectivity and appearance. The sodium'silicate coating may be affectedby heat in particular areas induced by a stylus carrying an electriccurrent. The heat may also be induced as indicated by a beam of radiantlight or heat which is directed onto different areas of the paper.

Although I specifically refer here to the use of a coating of sodiumsilicate which may contain water and glycerin, it is to be understoodthat this is byway of example only and that any coating having thesephysical properties may be employed, namely any coating, the appearanceof which may be radically changed in specified areas so as to producephysically distinct areas. By physical change here, I mean changes incontradistinction to the changes which may be induced by oxidation orother chemical change to produce different colors.

My invention further comprises preheating the paper and the coatingthereon immediately before the application thereto of the heat foreffecting the color change. I have found that if the heat sensitivematerial is preheated to almost the point where it will change color,just before the heat from the signal transmitted by the stylus isapplied, faster recording can be had or large recordings may be made inthe same time.

Further by means of this preheating of the coating to almost the pointof color change I may employ a weaker radiant heat, or a weaker current,when current is employed for effecting the heating, to effect threcording.

For example, the platen in back of the paper may be heated along theline where the recording is just thereafter to be produced andspecifically it may be heated in an area of two lines width, includingthe line which is being converted and the width of one line therebelow,the heat being begun just before and continuing until the line isrecorded. I have found that this preheating of the heat sensitive paperacts as an accelerator of the color change in the paper when it issubjected to the heat from the stylus or the radiant heat from asuitable radiant heat source, and I can, as pointed out, obtain fasterrecordings and better recordings even while using lower heat impulses asthe color change producing means.

When I employ a radiant heat source in lieu of the stylus which contactsthe recording paper I may obtain enlargements or large reproductions ofthe printing or picture to be reproduced. This is because the beam ofradiant heat can be far longer than a stylus arm. Instead of being, forexample, of an inch wide and four inches long, which may be thedimension of the stylus, the beam of radiant heat may ,be of an inchwide and 40 inches long.

By means of the preheating of the recording paper which I have describedabove, the recording paper which I have described above, the recordingpaper is rendered very sensitiv and the amount of heat transmitted overthis long radiant beam is sufiicient to induce the desired color2,317,789 changes in the specified areas. Thus, for example, foreducational purposes a class might view a recording at a distance of anumber 01- feet.

In lieu of using the longer radiant beam for enlargements as pointed outabove, I may employ it to obtain more columns of copy. This is because,although a stylus which is limited by its length to producing in arcuatemovement approximately two columns of recording, the beam of radiantheat is capablegof producing many more columns because of its greaterdistance of travel.

Thus it can be seen that the novel recording means and the novelrecording paper is capable of many variations within the scope of myinvention. I do not intend to be limited to the particular heatsensitive paper and coatings which I have set forth but have given theseby way of example only.

Further, I'have exampled as my means for producing the physical changein the recording paper, heat in the form of contact heat, conducted heatand radiant heat. The radiant heat may be induced in any manner, as forexample, from a. light source or from a reflecting source or infra-redmeans, and other heating sources may also be employed.

I have given these various means for heating by way of example forinducing the physical changes in the recording paper and intend toinclude all mechanical equivalents within the scope of my invention.

I claim:

1. -A reproduction paper comprising a backing and a heat sensitivecoating, which under the infiuence of heat forms bubbles, positionedthereon.

2. A reproduction paper comprising a backing and a coating of'sodiumsilicate containing water positioned thereon.

3. A reproduction paper comprising an electrocoriductive backing and acoating of sodium silicate containing water positioned thereon.

7 4. A reproduction paper comprising carbon impregnated paper and sodiumsilicate containing water positioned thereon.

5. A reproduction paper comprising a carbon impregnated paper and sodiumsilicate containing water containing a small amount of glycerinepositioned thereon.

6. A reproduction paper comprising a carbon impregnated paper and sodiumsilicate containing water containing about one-half to one per 7 cent ofglycerine positioned thereon.

ROBERT H. MARRIOTT.

